How to configure a BGP peer to set up connections with a local end using a fake AS number on S series switches

For S series switches that support BGP, the peer fake-as command configures the specified peer to establish a connection with the local end using a fake AS number.
Carriers often use this command to change network deployment scenarios. For example, when carrier A acquires carrier B, the AS number of carrier B needs to be changed to that of carrier A because the two carriers are located in different ASs. However, during network merging, the BGP peers of carrier B located in other ASs may not modify local BGP configurations immediately. In this case, the connection with these peers will be interrupted.
To ensure smooth network merging, you can run the peer fake-as command on the ASBR of carrier B to set the AS number of carrier B to a fake AS number of carrier A so that BGP peers of carrier B can continue to establish connections using the fake AS number.
Set a 2-byte fake AS number for a peer.
[HUAWEI] bgp 100
[HUAWEI-bgp] peer as-number 200
[HUAWEI-bgp] peer fake-as 99

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